Neufeld Zoltan, Haynes Peter H., Tel Tamas
Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Silver Street, Cambridge CB3 9EW, United Kingdom.
Chaos. 2002 Jun;12(2):426-438. doi: 10.1063/1.1476949.
We study the evolution of a localized perturbation in a chemical system with multiple homogeneous steady states, in the presence of stirring by a fluid flow. Two distinct regimes are found as the rate of stirring is varied relative to the rate of the chemical reaction. When the stirring is fast localized perturbations decay towards a spatially homogeneous state. When the stirring is slow (or fast reaction) localized perturbations propagate by advection in form of a filament with a roughly constant width and exponentially increasing length. The width of the filament depends on the stirring rate and reaction rate but is independent of the initial perturbation. We investigate this problem numerically in both closed and open flow systems and explain the results using a one-dimensional "mean-strain" model for the transverse profile of the filament that captures the interplay between the propagation of the reaction-diffusion front and the stretching due to chaotic advection. (c) 2002 American Institute of Physics.
我们研究了在具有多个均匀稳态的化学系统中，存在流体流动搅拌时局部扰动的演化。随着搅拌速率相对于化学反应速率的变化，发现了两种不同的状态。当搅拌快速时，局部扰动朝着空间均匀状态衰减。当搅拌缓慢（或反应快速）时，局部扰动以具有大致恒定宽度和指数增长长度的细丝形式通过平流传播。细丝的宽度取决于搅拌速率和反应速率，但与初始扰动无关。我们在封闭和开放流动系统中对该问题进行了数值研究，并使用一维“平均应变”模型来解释细丝横向分布的结果，该模型捕捉了反应扩散前沿的传播与混沌平流引起的拉伸之间的相互作用。（c）2002美国物理研究所。
